Coating apparatus

ABSTRACT

Substantially parallel conveyor elements are spaced apart for reception between them of the threaded shanks of fasteners, the heads of which are jointly supported on the elements. Throughout the article receiving portion of the conveyor, these elements are sufficiently spaced apart for free reception between them of the fastener shanks and to permit relative movement of the fasteners along the conveyor by an escapement mechanism to effect uniform spacing of the fasteners. Subsequently, the elements are urged toward each other and in gripping engagement with the shanks so that movement of one conveyor element relative to the other positively rotates the shanks and carries them in rolling engagement with the surface of a stationary applicator from which the coating material is transferred to the shanks. Subsequently, the shanks are carried with their applied coatings in operative engagement with the surface of a stationary smoothing device which also controls the coating thickness. By continuously moistening the surface of the smoothing device with a suitable liquid, adherence of the coating to such surface is prevented. After departure of th articles from the smoothing device and before their discharge from the conveyor, the applied coatings are sprayed with a suitable firming or hardening agent to minimize smearing or damaging of the applied coatings before same are fully cured.

United States Patent [191 Batson et a1. 9

[4 1 Mar. 5, 1974 COATING APPARATUS Inventors: Robert E. Batson, Newington;

Girard S. Haviland, West Hartford, both of Conn; David Matchett, West Springfield, Mass.

Primary ExaminerL0uis K. Rimrodt Attorney, Agent, or Firm watson, Cole, Grindle &

Watson ABSTRACT Substantially parallel conveyor elements are spaced apart for reception between them of the threaded shanks of fasteners, the heads of which are jointly supported on the elements. Throughout the article receiving portion of the conveyor, these elements are sufficiently spaced apart for free reception between them of the fastener shanks and to permit relative movement of the fasteners along the conveyor by an escapement mechanism to effect uniform spacing of the fasteners. Subsequently, the elements are urged toward each other and in gripping engagement with the shanks so that movement of one conveyor element relative to the other positively rotates the shanks and carries them in rolling engagement with the surface of a stationary applicator from which the coating mate rial is transferred to the shanks. Subsequently, the shanks are carried with their applied coatings in operative engagement with the surface of a stationary smoothing device which also controls the coating thickness. By continuously moistening the surface of the smoothing device with a suitable liquid, adherence of the coating to such surface is prevented. After departure of th articles from the smoothing device and before their discharge from the conveyor, the applied coatings are sprayed with a suitable firming or hardening agent to minimize smearing or damaging of the applied coatings before same are fully cured.

16 Claims, 8 Drawing Figures PAIENTEBNAR 51974 SHEUIOFZ 1 COATING APPARATUS This invention relates to an improved machine for applying coating material, such as looking compositions, to the shanks of headed articles such as bolts, rivets and other fasteners wherein the shanks are defined by external surfaces of revolution and are adapted to depend between relatively spaced conveyor elements which carry the articles past the coat applying apparatus.

While the machine is specifically illustrated and described in the present application in its preferred use for applying bands of coating material around the threaded shanks of conventional bolts for the purpose of interlocking with other threaded members, it manifestly is adapted for use also, in applying other coatings to the shanks of various other articles, provided with heads or enlargements whereby they may be supported from and carried by the conveyor.

The machine herein specifically disclosed, was devised and has for its primary object to overcome the problem of applying a coating material of viscuous or paste-like consistency to the shank of a headed fastener or other article, while confining it to a predetermined axial location on the article shank, so that when applied toa threaded fastener, for instance, the threads at the lead end of the threaded shank may be free of coating to avoid interference with its initial engagement with a cooperating threaded member. It will nevertheless be understood and readily apparent that a machine in accordance with the invention is also readily adaptable for use in applying coatings of varying consistencies and viscosities It is a further object to provide such a machine which will control the thickness of the coating material applied to the article shank; also to provide such a machine which includes a novel means for removing excess coating material both from the applicator and from the article shanks.

Further incidental objects are: to utilize the movement of the articles with respect to the coating applicator for urging'excess coating material toward a point of removal; to provide means for moistening the surface of the smoothing device to prevent adhesion of the coating material thereto and, subsequently, to apply to the smooth coating a suitable firming or hardening agent whereby-to enable theapplied coating better to resist smearing and deformation incident to discharge from the conveyor and further handling.

SUMMARY OF THE INVENTION With the foregoing objects in mind, the invention comprises a novel conveyor for carrying the fasteners or other articles past the several stationary article treatment points, or stations. The conveyor comprises parallel conveyor elements spaced apart for reception between them of the article shanks, with the articles jointly supported from these elements by their respective heads or enlargements. At the article receiving portion of the conveyor, these conveyor elements may be sufficiently spaced apart to permit relative movement of the articles and uniform spacing thereof on the conveyor by suitable escapement or spacing mechanism.

During subsequent movement of the articles past their coating and smoothing stations or locations, means are provided for urging the conveyor elements relatively toward each other for frictional gripping engagement with the shanks disposed between them. Since one conveyor element is moved relative to the other along the path of movement of the articles, a positive rotation is imparted to the respective shanks. A coating applicator fixedly supported adjacent the conveyor and having an applicator surface disposed parallel to the path of movement of the conveyed article, is supplied with the coating material which is transferred to the rotating articles. This surface may be somewhat spaced from the shanks of the articles or in tangential relation with the respective shanks for rolling engagement by the surfaces. of revolution of the respective shanks.

A fixedly positioned smoothing device has a similarly disposed smoothsurface supported at a predetermined distance from the axes of the respective shanks for smoothing engagement with the surfaces of the applied coatings and also controls the thickness of said coatings.

In its preferred form, the coating applicator is provided on its operative surface, with an opening or chan nel through which the coatingmaterial from a suitable source of supply is exuded to be spread across the surface by the article shanks incident to their conveying movement, such movement also being relied upon to carry excess coating material to a channel which traverses such operative face and through which a high velocity jet of fluid is directed to entrain and carry away excess coating material both from the article shanks and from the coating applicator. As will be understood, however, further types of coating applicators may be employed within the broad concept of the invention without departing therefrom.

The preferred form of smoothing device is formed with a smoothing surface adapted for rolling engagement with the applied coating at a location parallel to the path pursued by the shank axes and spaced at a predetermined distance therefrom to thereby govern the thickness of the finished coating. Any suitable means may be employed for maintaining on such surface a suitable liquid adapted for preventing adherence of the coating to the surface. Again it will be understood that the specific form of the coating smoothing device is subject to variation without departing from the broad scope of the invention.

DESCRIPTION OF THE DRAWINGS The foregiong and other novel features and advantages of the invention are now more particularly described with reference to the accompanying drawing, in which:

FIG. 1 is an elevation of a work piece or article adapted to be acted upon by the present invention and here exemplified by a conventional bolt, having a coating of material applied to its shank by the apparatus of the invention.

FIG. 2 is a generally diagrammatic illustration of the novel machine and apparatus of the invention.

FIG. 2a is a fragmentary perspective view illustrating the manner in which the work pieces are simultaneously gripped and rotated during their movement past the several work treating stations and/or devices.

FIG. 3 is a front elevation of the machine or apparatus.

FIG. 4 is an enlarged fragmentary plan view of the coating applicator and its support means.

FIG. 5 is a front elevation of the coating applicator.

FIG. 6 is a perspective view, partly in section, of the coating applicator, showing its mode of cooperation with the shank of a bolt, and

FIG. 7 is a perspective view, partly in section, of the smoothing device, showing its mode of cooperation with a bolt shank, the head of the bolt being omitted for purposes of clarity.

Referring now to the accompanying drawings, and

first considering the diagrammatic view of the invention, as set forth in FIG. 2, it will be seen that the invention comprises a conveyor or conveying mechanism 10 adapted torreceive a multiplicity of articles or work pieces W in succession from a conventional supply chute ll, vibratory feed hopper 12 and an inclined conveyor chute 14. The work pieces'or articles herein specifically illustrated, consist of similarly proportioned threaded fasteners W such as shown in FIG. 1, it being the function of the apparatus of FIG. 2 to apply to the threaded shank of each such bolt or threaded article a band B of coating material around the threaded shank 15 of the fastener W at a location preferably spaced from its head 17, as well as from the free end of its shank 15, to leave the terminal thread or thread convolutions uncovered for entry into a threaded opening without interference by the coating.

The hopper and chute 12 and 14 operate in customary manner to deliver a stream of fasteners W onto the receiving portion A of the conveyor 10, with the fasteners uniformly oriented in such manner that their threaded shanks 15 will normally be directed downwardly between the relatively spaced and generally horizontally extending operative conveyor elements 18 and 20 of the conveyor 10, with the relatively larger diameter head 17 of each bolt resting on said conveyor elements and the threaded shank 15 depending vertically between said elements, in the manner illustrated in FIG. 2a.

The conveyor 10 is driven at a normally constant rate by an electric drive motor 22 in a direction toward the left as shown by the arrow in FIG. 2, and preferably carries the parts or fasteners progressively past a conventional escapement mechanism 24, which functions to temporarily retard the movement of certain closely spaced fasteners with respect to the conveyor, to achieve a uniform spacing between adjacent fasteners during their subsequent movement with the conveyor.

As the uniformly spaced fasteners or articles W leave the escapement mechanism 24, the conveyor 10 then carries each such fastener W successively past and in operative relation to a stationary coating applicator 26 positioned for operative engagement with the shanks of the successive bolts to apply the desired band B of coating material thereto; thence past and in operative engagement with a smoothing means or device 28, following which each such fastener is then carried by the conveyor past a suitable applicator, such as the spray nozzle 30 for applying a suitable firming agent to the outer surfaces of the successive bands B of coating material previously applied to the respective fastener shanks After leaving the spray station at nozzle 30, the fasteners or other articles arrive at the discharge end of the conveyor where they are delivered to an inclined and preferably laterally swingable discharge chute 32 which directs them into suitablevbins or containers.

By virtue of the firming or hardening of the outer surfaces of the respective bands B of material, they are better able to resist damage or deformation when discharged through chute 32.

From the foregoing general description of the machine, it will be apparent that the initial portion of the conveyor, onto which the fasteners are initially delivered from the feed hopper l2 and inclined chute 14, is such as to freely receive the threaded shanks 15 of the fasteners between the conveyor elements 18 and 20 and, also, to permit a relative sliding movement of the fasteners so that they may be retarded as necessary by the escapement mechanism 24 to achieve the desired uniform spacing between the conveyed fasteners. For purposes of convenience, the portion of the conveyor which thus receives and spaces the fasteners, will be designated as the receiving portion A of the conveyor.

Preferably, that portion of the conveyor 10 which moves past the coating applicator 26 and smoothing device 28, serves to firmly gripor clamp the threaded shanks of the fasteners to maintain their uniform spacing, as well as to maintain the threaded shanks of the fasteners in firm operative engagement with the coating applicator 26 and the smoothing device 28. At the same time, the conveyor functionsto achieve a constant positive rotation of each threaded shank about its axis, whereby its entire circumference (or any desired portion thereof) may move successively along and in rolling engagement or relation with each of the devices 26 and 28.

THE CONVEY-GIIW As above indicated, the conveyor 10 comprises the generally horizontally extending relatively parallel spaced conveyor elements 18 and 20. At least one of these elements 18 is driven by suitable means such as the motor 22 for operative movement through an endless circuit, at a velocity different than that of the cooperating conveyor element 20, whereby the work pieces W carried between these elements 18 and 20 will be rotated about the axes of their respective shanks 15. It will be apparent that the rate of rotation and the length of the operative portions of the coating applicator 26 and the smoothing block or device 28 will preferably be such that each work piece will be rotated through at least one complete revolution with its shank in operative engagement with the respective devices 26 and 28 when conveyed there past by the conveyor 10.

In the preferred embodiment herein illustrated, and as is best seen in FIG. 3, the conveyor 10, as well as the other components of the machine, are supported on a suitable rigid supporting frame.

For purposes of simplicity, both conveyor elements 18 and 20 are shown as comprising endless flexible cables, of which the cable or element 20 is supported around relatively spaced apart pulleys 33 and 35, while the conveyor element 18 is supported and guided for movement about the relatively spaced-apart pulleys 36 and 37, respectively. The pulleys 35 and 37 are conveniently supported in concentric manner on a common shaft 38, fixed to a bracket 40 which is suitably anchored to the horizontal supporting frame surface 34, the pulley 37 being rotatably journalled on the shaft 38.

The pulleys 33 and 36 in the embodiment here illustrated, are concentrically supported by the output shaft 42 of the conveyor drive motor 22 which, in turn, will be understood to be fixedly supported from the frame 34. In order to secure the desired movement between the conveyor elements 18 and 20, the pulley 36, which supports the receiving end of the conveyor element 18, is fixed on the shaft 42 for rotation therewith, to impart a constant conveying movement to the upper operative drive portion of the conveyor element 18 toward its discharge end, or toward the left, as indicated by the arrow in FIG. 2. The conveyor 20 in the present embodiment is preferably held stationary as by anchor element 44, securing it to the horizontal frame surface 34.

The conveyor element 18, preferably, is tensioned, as exemplified in FIG. 3, by a resiliently upwardly biased idler, wheel 46, carried by bracket 48 at the upper end of the piston rod 50 of a conventional pneumatic piston and cylinder structure.

With the preferred arrangement of the conveyor elements l8 and 20 as above described, it will be apparent that the receiving portion A of the conveyor adjacent its right hand end as seen in FIG. 2, is arranged with the conveyor elements 18 and 20 spaced apart a distance somewhat greater than the diameters of the work piece shanks 15, but less than the diameters of their heads 17, so that the conveyor 10 supports the articles W by their heads.

7 It will be seen that the relative movement between the conveyor elements 18 and 20 and the frictional engagement of these elements with the enlarged portions or heads 17 of the respective work pieces will impart a rotating movement to the respective work pieces and such engagement may constitute the only rotational force applied to the work pieces in certain installations. The aforesaid relative spacing between the conveyor elements 18 and 20, at the receiving portion of the conveyor, in addition to permitting ready reception of the work piece shanks between the conveyor elements 18 and 20, also permits a relative sliding movement of the work pieces on the conveyor so that where an escape ment mechanism such as 24, is employed, such mechanism may readily retard the movement of certain closely spaced work pieces, releasing them individually and at relatively uniform spacings, or intervals for subsequent movement with the conveyor through the coating applying section C ofthe machine, to be acted upon in turn, by the coating applicator 26 and smoothing device 28.

The spacing between the conveyor elements 18 and 20 may be uniform throughout the entire length of the conveyor and so selected as above mentioned to permit free sliding of the elements or work pieces on the con veyor. I

However, in accordance with an important feature of theinvention, as hereinafter more fully explained, that portion C of the conveyor which moves past the coating applicator 26 and smoothing device 28, preferably is arranged to firmly grip or clamp the work piece shanks between them to maintain the uniform spacing of the shanks as established by the escapement mechanism 24 when the conveyor is moved past the devices 26 and 28, as well as to maintain the shanks parallel to and in flush operative engagement with the cooperating surfaces of the coating applicator 26 and smoothing device 28. To this end, the conveyor element 18 is deflected or urged toward conveyor element by rollers 52 and 54 rotatably supported by brackets 56 and 58, respectively, extending from standards 60 and 62.

I Moreover, due to the gripping action of the conveyor elements 18 and 20 directly on the work piece shanks 15, the rotation of each work piece will be transmitted thereto through its shank rather than through its head, to achieve substantially a true rolling action of the shanks in succession across the operative surfaces of the devices 26 and 28, respectively. Such positive rotation of the workpieces will ensure that the work pieces will undergo rotation through uniform angles during their movement in engagement with each of the said devices 26 and 28, the lengths of which preferably are selected to achieve a complete encircling of each shank 15 by a band B of coating material.

THE COATING APPLICATOR The coating applicator 26 (illustrated in detail in FIGS. 4, 5 and 6), comprises a block which, in the pres ent instance is secured by bolts 64 to a standard 56 extending upwardly from the machine frame 34, a flat spacer plate and gasket 66 of suitable material being interposed between the two. The applicator block is I formed to provide an internal reservoir 68 (FIGS. 4 and 6) which opens through the rear face of the block and is closed by the plate 66. The coating material is delivered under pressure into this reservoir 68, preferably by a pulsating pump 70 which as shown in FIG. 2, withdraws the coating material or slurry from a suitable slurry supply source 72 through a conduit 74 and delivers it under pressure into the reservoir 68 through a passage 76, (FIG. 4) and which will be understood tov communicate with the output of the pump 70. The operative surface 78 of the applicator 26 is in a vertical plane tangent to'the surface of revolution which defines the work piece shanks 15 and extends parallel to the movement of the conveyor and work pieces, so that a portion of the surface of each shank is in rolling engagement with the surface 78 through which the slurry or coating material is applied in band form to the shank. Preferably, the leading end of the block is chamfered to provide a ramp 79 for iaaih'gffiwori piece shanks 15 onto the surface 78.

In order to maintain an adequate supply of slurry on the operative face of the applicator 26, the said face 78 is formed in the preferred embodiment with a generally zig zag groove 80 having at appropriate locations thereon a series of passages or bores 82 extending from the bottom of said groove into the reservoir 68.

Thus, as each work piece shank 15 moves along the applicator surface 78 in the direction shown by the arrow in FIG. 6, the coating material delivered into the zig zag groove 80 will tend to exude therefrom to be distributed over the surface 78 by the successive work piece shanks, and at the same time will be applied to the respective shanksin the form of a circular band B. Where the shanks are threaded, as illustrated in the accompanying drawings, the crests of the threads thereon will closely approach, and preferably will contact the operative surface 78. The coating on the surface 78 normally will be of sufficient depth that the rolling engagement of the shank with the said surface will cause the coating material or slurry to fully occupy the spaces between the roots and crests of adjoining threads. Further, as will be apparent from FIG. 6, the width of the surface 78 will determine the width of the bands B to be applied, while the particular height or location of the said surface 78 will be so selected as to apply the band B at the desired predetermined location, preferably medially of the opposite ends or extremities of the shanks 15.

Manifestly, the disposition and shape of the distributing groove 80 and its associated passages 82, is subject to quite wide variation as to both shape and dimension and there may be more than one such groove, all in accordance with such variables as the nature and viscosity of the coating material, the width and depth of the bands B to be applied to the shanks 15, the exact shape and nature of such shanks, and the number of such shanks to which the coating is applied per unit of time.

Where the coating material is of a substantially viscous nature, it is desirable to provide a suitable means adjacent to the discharge end of the coating applicator 26 for removing excess coating material which may cling to the shanks to form globs or droplets and which may act by gravity to extend the band B or portions thereof downwardly toward the free end of the shank 15 below the intended lower margin of the band B.

Accordingly, for the purpose of removing any excess of coating material immediately following the application of such material to the shanks, the coating block or applicator is formed with a channel 84 opening through its surface 78 and extending transversely to the direction of movement of the conveyor 10.

A high velocity jet of a suitable fluid such as air is directed from a nozzle 86 in a direction through and lengthwise of the channel 84, as illustrated by the arrows in FIG. 5. This fluid jet being at high velocity, is at a lower pressure than the ambient atmosphere and will serve to draw in and entrain any excess material from the work piece shanks 15 as well as from the surface 78 when the shanks move across the groove 84.

THE SMOOTHING DEVICE The smoothing device 28 which is located downstream from the coating applicator 26 in the direction of the conveyor move tnerinconsists essentially of a suitable body supported by the standard 62 which, in turn, has its base 63 anchored to the supporting frame 34. The device 28 has an operative smoothing surface 88 which, as shown in FIG. 7, is positioned for operative rolling smoothing engagement by the band B of coating material previously applied by the coating applicator 26. In the present instance, where the shank l constitutes the externally threaded stem of the bolt or screw, the surface 88 is of perfectly smooth flat configuration both in a direction axially of the rotating work piece shanks and also in a direction parallel to the movement of such shanks on the conveyor 10.

It will be noted that the coating device 28, as shown in FIG. 7 has a cut-away portion or channel 90 at its upper corner above the smoothing surface 88 to provide clearance for and to receive a conveyor element 20, whereby the smoothing surface 88 in the preferred embodiment projects beneath the element in a vertical plane parallel to that element and tangentially related to the rotating work piece shanks 15 and the coating material bands B thereon.

In order to prevent adhesion of the coating material to the surface 88, it is desirable to maintain on such sur face a thin coat of a suitable liquid, as for instance, water or isopropynal alcohol, ofa volatile nature, so as to evaporate from the coating shortly after completion of the smoothing action and thereby to avoid adversely affecting the qualities of the coating or coating material. Such a liquid coat may be continuously applied to the surface 88 by means of a suitably qupported spray nozzle 30 as shown in FIGS. 1 and 7.

MODE OF OPERATION be received upon conveyor 10 in irregularly spaced re-' lationship with some of the work pieces in substantially contiguous relationship to each other.

As the conveyor carries the work pieces to the escapement mechanism 24, a plurality of the work pieces normally will be backed up or retarded, by the escapement mechanism 24, without interfering with the motion of the conveyor, this obviously being possible because of the freely slidable relationship of the work pieces on the receiving portion A of the conveyor.

These backed up work pieces are released individu-' ally and successively for travel with the operative midportion or coating applying portion C of the conveyor at uniformly spaced intervals, preferably beong firmly frictionally gripped by the somewhat more closely spaced conveyor elements 18 and 20 during their travel through said coating portion, whereby the work pieces are maintained at the desired uniform spacings during their subsequent treatment and are positively rotated by virtue of the relative movement between the conveyor elements 18 and 20. Where, as in the preferred embodiment, one of the conveyor elements is stationary, the frictional engagement of the conveyor elements with the work piece shanks 15 gripped between them, will produce a positive rotation of the work pieces about the axes of their said shanks l5 and will produce a true rolling motion of the shanks across the operative surfaces of the coating applicator 26 and smoothing block 28. Such positive rotation is generally preferable to the type of rotation that would result primarily from yieldable frictional engagement between the heads 17 of the articles and the respective conveyor elements, as this obviously would not produce such a rolling motion of the shanks 15 as is here desired and, because of the yielding or sliding grip of the conveyor elements with the head, could produce an irregular rotation which could be slowed or even arrested where the coating material on the operative surface of the coating applicator 26 is of a particularly heavy or viscuous nature. As the shanks 15 move in succession along the operative surface 78 of the applicator 26, they will be coated with coating material exuded from the channel or groove 80, while urging any excess of the material in a direction toward the groove 84 so that any such excess of material on the surface 78 as well as any excess of material clinging to the shanks 15 is sucked into the negative pressure jet stream of fluid flowing through the channel 84, to be entrained and carried away in said jet stream so as not to flow to undesired locations on the shanks 15. The pump which supplies material to the coating applicator, is preferably actuated in any suitable manner to deliver a predetermined quantity of coating material to the applicator as each work piece is engaged thereby and, for this purpose, may be actuated by conventional means, incident to the approach of each work piece W to the coating block or applicator 26, to cause the pump 70 to deliver a predetermined quantity of coating material thereto.

As each work piece in succession moves from the coating applicator 26 into operative engagement with the smoothing device 28, the liquid coating which is sprayed onto the surface of the latter device will prevent adherance of the coating material to the smoothing block or device. Where the liquid coating is a solvent for the coating material it will necessarily result in a thinning or reduction of viscosity of the outer face of each coating B to facilitate the smoothing thereof. The

, volatile nature of the said liquid then causes it to evaporate into the atmosphere within a relatively short period of time so as not to interfere with the qualities or functions of the coating material However, since the evaporation of the coating liquid obviously will not be instantaneous, the nozzle 30 applies to the coating bands B of the respective work pieces a suitable hardeningor firming agent such as a suitable gelling agent, of a nature such as to effect a substantially immediate firming or hardening of a thin skin of material at the outer surface of the applied band B to better resist smearing or damaging of the coating bands B, during their subsequent handling.

Having thus described our invention, we claim:

1. A machine for applying a band of coating material around the shanks of headed articles, comprising a conveyor for receiving and transporting said articles past coating applying apparatus to a discharge station, and including in succession a receiving section for reception of articles to be coated, and a coating applying section; said conveyor comprising a pair of relatively horizontal and generally parallel conveyor elements, means supporting said elements in spaced relation; means for moving one said element relative to the other in a direction from said receiving section towards said coating applying section; said conveyor elements being spaced in said receiving section, a distance greater than the diameters of the threaded shanks of the fasteners, but less than the diameters of the fastener heads, to slidably support fasteners suspended by their heads from said conveyor elements and to freely receive the shanks of said fasteners between said conveyor elements; means for maintaining said elements in more closely spaced relation to eachother at said coating applying section than at said receiving section to frictionally grip the shanks of fasteners carried by the conveyor through said coating applying section, for positively feeding said fasteners in succession through said coating applying section, while maintaining the relative positions of said fasteners on the conveyor.

2. A machine as defined in claim 1, including an escapement mechanism adjacent said receiving section of the conveyor, for temporarily retarding the movement of certain said articles relative to the conveyor to achieve a predetermined uniform spacing between adjoining articles on the conveyor, said conveyor elements at the coating applying section thereafter gripping the shanks of said articles to maintain said uniform spacing and positively moving said articles in succession through said coating applying section.

3. A machine for applying a band of coating material around the shanks of headed articles, comprising a conveyor for receiving and transporting said articles past coating applying apparatus to a discharge station, and including in succession a receiving section for reception of articles to be coated, and a coating applying section; said conveyor comprising a pair of relatively horizontal and generally parallel conveyor elements, means supporting said elements in spaced relation; means for moving one said element relative to the other in a direction from said receiving section towards said coating applying section; said conveyor elements being spaced in said receiving section, a distance greater than the diameters of the threaded shanks of the fasteners, but less than the diameters of the fastener heads, to slidably support fasteners suspended by their heads from said conveyor elements and to freely receive the shanks of said fasteners between said conveyor elements; means for urging one of said conveyor elements toward the other at said coating applying section whereby to frictionally grip the shanks of fasteners carried by the conveyor through said coating applying section, for positively feeding said fasteners in succession through said coating applying section, while maintaining the relative positions of said fasteners on the conveyor; and a coating applicator having a vertically disposed flat surface, parallel to the conveyor movement at said coating applying station and in a plane tangent to the threaded shanks of the respective articles for successive engagement by said shanks, the relative movement between said conveyor elements, producing a positive rotation of said articles about the axes of their said shanks.

4. A machine as defined in claim 3, further including an escapement mechanism adjacent the said receiving portion for temporarily retarding the movement of certain said articles relative to the conveyor to achieve a uniform predetermined spacing between adjoining articles on the conveyor, said spacing thereafter being maintained by the gripping action of said conveyor elements in the coating applying section, said gripping action further maintaining the article shanks in vertically depending relation parallel to the flat surfaces of their tangentially related coating applicator.

5. A machine as defined in claim 3, in which the other said conveyor element is stationary and the threaded shanks of the said articles are rolled along such stationary section and across the tangentially related surface of said coating applicator.

6. A machine as defined in claim 3, including a smoothing block at said coating applying section downstream of the coating applicator in the direction of movement of the conveyor, said smoothing block having a vertically disposed flat surface in a plane tangent to the shanks of the respective articles for engagement by said shanks incident to their movement through the coating applying section.

7. The machine of claim 6, including means for continuously applying to the said flat surface of the smoothing block a liquid for preventing adhesion to the said surface of the coating material previously applied to the respective shanks by the coating applicator.

8. A machine as defined in claim 3, wherein said coating applicator is formed at its downstream end with a traversely extending channel opening through its said flat surface, there being means for directing a high velocity jet of fluid downwardly through said channel, to create a subatmospheric pressure for withdrawing excess coating material from the respective article shanks.

9. A machine as defined in claim 8, further including a spray nozzle directed toward the conveyor sections at a location between said smoothing block and the discharge station for applyinga liquid gelling agent to the bands of coating material around the respective shanks.

10. In a machine for applying a band of coating material around the shanks of headed fasteners, a coating applicator having an operative applicator surface, means for continuously supplying a viscous slurry of said coating material to said surface, conveyor means for moving headed fasteners along said applicator from one end to the other thereof with the shanks of said fasteners in tangential engagement with said surface, and means for rotating the said fasteners throughout their said engagement with the applicator, said applicator being provided with a downwardly directed channel in its said face opening through its lower edge, and means for maintaining a high velocity jet of fluid through said channel to remove excess coating material from the respective shanks. I

11. A machine for applying a band of coating material around the shanks of similarly proportioned headed fasteners, comprising a conveyor which includes a pair of flexible conveyor elements having substantially parallel horizontal operative runs spaced apart in a horizontal plane, one of said elements being endless and guided for movement through an endless circuit, and means for driving said one element at a constant speed through said circuit, the other said element being stationary; said conveyor defining a fastener receiving section adjacent one end thereof, wherein said parallel conveyor runs are relatively spaced apart a distance greater than the diameters of the said shanks, but less than the diameters of the fastener heads, to permit relative sliding movement between the conveyor and fasteners which are jointly suspended by their heads from said parallel conveyor runs with their respective shanks depending between said runs; an escapement mechanism adjacent said receiving section of the conveyor for temporarily retarding the movement of certain fasteners on said conveyor to achieve a predetermined spacing between successive fasteners; means downstream of the escapement mechanism for urging one conveyor run horizontally toward the other throughout an operative coating applying section of the conveyor movement, whereby to frictionally grip the fastener shanks between them to produce rotation of said shanks incident to relative movement between said parallel conveyor runs; and coating applicator means supported beneath and parallel to one said run at said operative coating applying section of the conveyor movement in position for rolling engagement by the shanks of the fasteners carried by the conveyor.

12. In a machine for applying a band of coating material around the shanks of headed fasteners, the combination comprising a conveyor which includes a pair of flexible conveyor elements having substantially parallel horizontal operative runs spaced apart in a horizontal plane, means for guiding one of said conveyor elements through an endless circuit, the other said element being stationary; one of said elements being horizontally flexible toward and away from the other; said conveyor defining a fastener receiving section adjacent one end of said operative run, said runs being relatively spaced apart at said section a distance greater than the diameters of the said shanks but less than the diameters of the fastener heads, to receive between them with clearance the said shanks of the fasteners which are jointly suspended by their heads from said conveyor runs so as to permit slidingmovement of the fasteners on the conveyor; an escapement mechanism adjacent said receiving section for temporarily retarding the movement of fasteners on said conveyor to achieve predetermined uniform spacing between successive fasteners; and means down-stream of the escapement mechanism with respect to the conveyor movement for urging a portion of the operative run of said horizontally flexible element toward the other said element throughout an operative portion of the conveyor movement, whereby to frictionally grip the fastener shanks between said elements to retain the predetermined spacing between said fasteners and to produce rotation of said fasteners incident to the relative movement between said conveyor elements.

13. Apparatus for applying coating material to the shanks of headed articles, wherein the shanks are defined by external surfaces of revolution, respectively, said apparatus comprising a conveyor for carrying the articles along a predetermined path of movement, said conveyor comprising parallel conveying elements, defining a receiving section in which said elements are spaced apart for free reception between them of the article shanks with the articles jointly supported on said elements by their respective heads, and a coating applying section, means maintaining said elements in more closely spaced relation to each other at said coating applying section than at said receiving section for frictional gripping engagement with the shanks in said coating applying section, means for moving one said conveyor element along said path, relative to the other said element, wherebyto rotate the shanks about the axes of their respective surfaces of revolution; a coating applicator fixedly supported adjacent said conveyor and having an applicator surface disposed parallel to the paths of movement of the article shanks, and means for supplying coating material to said applicator surface for transfer to said article shanks.

14. Apparatus as defined in claim 13, wherein said applicator surface is disposed in tangential relation to the said surfaces of revolution in position for rolling engagement by said surfaces.

15. Apparatus as defined in claim 14, wherein a slot extends across and opens through said applicator surface at the downstream end of the applicator with respect to the conveyor movement, and means for flowing a high velocity jet of fluid through said slot, generally parallel to said 'applicator surface for entraining and removing excess coating material from the said article shanks.

16. Apparatus as defined in claim 13, further including a smoothing device fixedly supported adjacent said conveyor and having a smoothing surface disposed parallel to the path of movement of the said shanks, and spaced at a predetermined distance from the rotational axes of the respective shanks for rolling engagement with the previously applied coatings for smoothing said coatings and controlling the thickness thereof. 

1. A machine for applying a band of coating material around the shanks of headed articles, comprising a conveyor for receiving and transporting said articles past coating applying apparatus to a discharge station, and including in succession a receiving section for reception of articles to be coated, and a coating applying section; said conveyor comprising a pair of relatively horizontal and generally parallel conveyor elements, means supporting said elements in spaced relation; means for moving one said element relative to the other in a direction from said receiving section towards said coating applying section; said conveyor elements being spaced in said receiving section, a distance greater than the diameters of the threaded shanks of the fasteners, but less than the diameters of the fastener heads, to slidably support fasteners suspended by their heads from said conveyor elements and to freely receive the shanks of said fasteners between said conveyor elements; means for maintaining said elements in more closely spaced relation to each other at said coating applying section than at said receiving section to frictionally grip the shanks of fasteners carried by the conveyor through said coating applying section, for positively feeding said fasteners in succession through said coating applying section, while maintaining the relative positions of said fasteners on the conveyor.
 2. A machine as defined in claim 1, including an escapement mechanism adjacent said receiving section of the conveyor, for temporarily retarding the movement of certain said articles relative to the conveyor to achieve a predetermined uniform spacing between adjoining articles on the conveyor, said conveyor elements at the coating applying section thereafter gripping the shanks of said articles to maintain said uniform spacing and positively moving said articles in succession through said coating applying section.
 3. A machine for applying a band of coating material around the shanks of headed articles, comprising a conveyor for receiving and transporting said articles past coating applying apparatus to a discharge station, and including in succession a receiving section for reception of articles to be coated, and a coating applying section; said conveyor comprising a pair of relatively horizontal and generally parallel conveyor elements, means supporting said elements in spaced relation; means for moving one said element relative to the other in a direction from said receiving section towards said coating applying section; said conveyor elements being spaced in said receiving section, a distance greater than the diameters of the threaded shanks of the fasteners, but less than the diameters of the fastener heads, to alidably support fasteners suspended by their heads from said conveyor elements and to freely receive the shanks of said fasteners between said conveyor elements; means for urging one of said conveyor elements toward the other at said coating applying section whereby to frictionally grip the shanks of fasteners carried by the conveyor through said coating applying section, for positively feeding said fasteners in succession through said coating applying section, while maintaining the relative positions of said fasteners on the conveyor; and a coating applicator having a vertically disposed flat surface, parallel to the conveyor movement at said coating applying station and in a plane tangent to the threaded shanks of the respective articles for successive engagement by said shanks, the relative movement between said conveyor elements, producing a positive rotation of said articles about the axes of their said shanks.
 4. A machine as defined in claim 3, further including an escapement mechanism adjacent the said receiving portion for temporarily retarding the movement of certain said articles relative to the conveyor to achieve a uniform predetermined spacing between adjoining articles on the conveyor, said spacing thereafter being maintained by the gripping action of said conveyor elements in the coating applying section, said gripping action further maintaining the article shanks in vertically depending relation parallel to the flat surfaces of their tangentially related coating applicator.
 5. A machine as defined in claim 3, in which the other said conveyor element is stationary and the threaded shanks of the said articles are rolled along such stationary section and across the tangentially related surface of said coating applicator.
 6. A machine as defined in claim 3, including a smoothing block at said coating applying section down-stream of the coating applicator in the direction of movement of the conveyor, said smoothing block having a vertically disposed flat surface in a plane tangent to the shanks of the respective articles for engagement by said shanks incident to their movement through the coating applying section.
 7. The machine of claim 6, including means for continuously applying to the said flat surface of the smoothing block a liquid for preventing adhesion to the said surface of the coating material previously applied to the respective shanks by the coating applicator.
 8. A machine as defined in claim 3, wherein said coating applicator is formed at its downstream end with a traversely extending channel opening through its said flat surface, there being means for directing a high velocity jet of fluid downwardly through said channel, to create a subatmospheric pressure for withdrawing excess coating material fRom the respective article shanks.
 9. A machine as defined in claim 8, further including a spray nozzle directed toward the conveyor sections at a location between said smoothing block and the discharge station for applying a liquid gelling agent to the bands of coating material around the respective shanks.
 10. In a machine for applying a band of coating material around the shanks of headed fasteners, a coating applicator having an operative applicator surface, means for continuously supplying a viscous slurry of said coating material to said surface, conveyor means for moving headed fasteners along said applicator from one end to the other thereof with the shanks of said fasteners in tangential engagement with said surface, and means for rotating the said fasteners throughout their said engagement with the applicator, said applicator being provided with a downwardly directed channel in its said face opening through its lower edge, and means for maintaining a high velocity jet of fluid through said channel to remove excess coating material from the respective shanks.
 11. A machine for applying a band of coating material around the shanks of similarly proportioned headed fasteners, comprising a conveyor which includes a pair of flexible conveyor elements having substantially parallel horizontal operative runs spaced apart in a horizontal plane, one of said elements being endless and guided for movement through an endless circuit, and means for driving said one element at a constant speed through said circuit, the other said element being stationary; said conveyor defining a fastener receiving section adjacent one end thereof, wherein said parallel conveyor runs are relatively spaced apart a distance greater than the diameters of the said shanks, but less than the diameters of the fastener heads, to permit relative sliding movement between the conveyor and fasteners which are jointly suspended by their heads from said parallel conveyor runs with their respective shanks depending between said runs; an escapement mechanism adjacent said receiving section of the conveyor for temporarily retarding the movement of certain fasteners on said conveyor to achieve a predetermined spacing between successive fasteners; means downstream of the escapement mechanism for urging one conveyor run horizontally toward the other throughout an operative coating applying section of the conveyor movement, whereby to frictionally grip the fastener shanks between them to produce rotation of said shanks incident to relative movement between said parallel conveyor runs; and coating applicator means supported beneath and parallel to one said run at said operative coating applying section of the conveyor movement in position for rolling engagement by the shanks of the fasteners carried by the conveyor.
 12. In a machine for applying a band of coating material around the shanks of headed fasteners, the combination comprising a conveyor which includes a pair of flexible conveyor elements having substantially parallel horizontal operative runs spaced apart in a horizontal plane, means for guiding one of said conveyor elements through an endless circuit, the other said element being stationary; one of said elements being horizontally flexible toward and away from the other; said conveyor defining a fastener receiving section adjacent one end of said operative run, said runs being relatively spaced apart at said section a distance greater than the diameters of the said shanks but less than the diameters of the fastener heads, to receive between them with clearance the said shanks of the fasteners which are jointly suspended by their heads from said conveyor runs so as to permit sliding movement of the fasteners on the conveyor; an escapement mechanism adjacent said receiving section for temporarily retarding the movement of fasteners on said conveyor to achieve predetermined uniform spacing between successive fasteners; and means down-stream of the escapement mechanism with respect to the conveyor mOvement for urging a portion of the operative run of said horizontally flexible element toward the other said element throughout an operative portion of the conveyor movement, whereby to frictionally grip the fastener shanks between said elements to retain the predetermined spacing between said fasteners and to produce rotation of said fasteners incident to the relative movement between said conveyor elements.
 13. Apparatus for applying coating material to the shanks of headed articles, wherein the shanks are defined by external surfaces of revolution, respectively, said apparatus comprising a conveyor for carrying the articles along a predetermined path of movement, said conveyor comprising parallel conveying elements, defining a receiving section in which said elements are spaced apart for free reception between them of the article shanks with the articles jointly supported on said elements by their respective heads, and a coating applying section, means maintaining said elements in more closely spaced relation to each other at said coating applying section than at said receiving section for frictional gripping engagement with the shanks in said coating applying section, means for moving one said conveyor element along said path, relative to the other said element, whereby to rotate the shanks about the axes of their respective surfaces of revolution; a coating applicator fixedly supported adjacent said conveyor and having an applicator surface disposed parallel to the paths of movement of the article shanks, and means for supplying coating material to said applicator surface for transfer to said article shanks.
 14. Apparatus as defined in claim 13, wherein said applicator surface is disposed in tangential relation to the said surfaces of revolution in position for rolling engagement by said surfaces.
 15. Apparatus as defined in claim 14, wherein a slot extends across and opens through said applicator surface at the downstream end of the applicator with respect to the conveyor movement, and means for flowing a high velocity jet of fluid through said slot, generally parallel to said applicator surface for entraining and removing excess coating material from the said article shanks.
 16. Apparatus as defined in claim 13, further including a smoothing device fixedly supported adjacent said conveyor and having a smoothing surface disposed parallel to the path of movement of the said shanks, and spaced at a predetermined distance from the rotational axes of the respective shanks for rolling engagement with the previously applied coatings for smoothing said coatings and controlling the thickness thereof. 